In recent years with the advent of mega-retailers and mass merchandising, packaging has rapidly evolved. Today, more than ever, packaging is an extension of the marketing effort and product differentiation is often more important than the product itself. Thus product differentiation through enhanced printed graphics on the packaging is critical.
In the paper industry, the term xe2x80x9cpaperboardxe2x80x9d is generally considered to include container board, such as corrugated boxes and linerboard, as well as boxboard, which includes beverage carriers, cereal boxes, milk cartons, small folded boxes, and the like. It has been recognized that sharp, precise graphics cannot be obtained when printing directly on paperboard products, due to the fact that the paperboard printing surface is relatively rough or uneven, as compared with clay coated paper. Further, paperboard normally has a grey or brown color, and printing directly on the darker color of the paperboard will tend to distract from the resolution of the graphics. To meet the demand for improved graphics, there have been attempts to use white packaging substrates produced from bleached pulp. While the white substrates provide enhanced printing surfaces, as compared with the normal brown and grey paperboard, the white paperboard is considerably more costly to produce and lacks the strength of an unbleached pulp substrate. Further, paperboard is relatively thick as compared to publication paper and cannot be printed through use of the modem high speed printing processes that are used for paper printing.
Beverage carrier, which is a type of paperboard, is designed to contain beverage cans in six-packs, twelve-packs, cases, or the like. As the beverage cans have considerable weight, it is important that the beverage have high tear strength. The typical beverage carrier is a two-ply product, generally consisting of a base ply of virgin Kraft formed from long soft wood fibers, which provide the increased tear strength, and an outer or top ply, generally formed of shorter fiber hardwood. The top ply typically receives a clay coating and graphics are then printed on the clay coated top ply. The printed sheet is then die-cut into sections and each section is folded and glued into the shape of a box or container to subsequently receive the beverage cans.
Due to the relatively rough surface of the coated paperboard, as compared to clay coated paper, the printed graphics do not have the fine or sharp resolution compared to graphics printed on paper. Further, it is difficult to produce the clay coated paperboard. Because of the dark color of the substrate, the clay coating must be thick enough to mask the color, but if the clay coating is too thick, it may crack and adversely effect the printed graphics.
A further problem in the production of beverage carrier is that the printing cannot be done on high speed offset presses as with paper, so that less sophisticated, lower speed printing equipment must be employed.
Thus, there has been a distinct need for paperboard packaging having enhanced graphics.
The present invention is directed to a laminated paperboard package having enhanced graphics and to a method of producing the same. It is an object of the present invention to use metalized paper to enhance the quality of the packaging. U.S. patent application Ser. No. 09/632,140, described the use of publication or other types of freesheet paper. The present invention provides a metalized paper to improve the graphic image. Metalized paper has a particular advantage in beverage packaging, where beer bottles contain metalized label paper (label paper is a type of freesheet paper) to improve the graphics by incorporating the metal substance in the design. Employing metalized paper has a functional advantage of being able to employ print methods and styles from the beer bottle label paper printing to the secondary carton printing.
The present invention relates to a laminated carton comprising a laminated composite sheet folded and secured in the configuration of a box. The sheet comprises a non-corrugated base layer of unbleached cellulosic fibers and has an inner surface and an outer surface. The laminated carton further comprises an outer layer of separately formed non-corrugated metalized paper having an inner surface and an outer surface with printed graphics disposed on the outer surface of the outer layer. An adhesive is disposed between the inner surface of the outer layer and the outer surface of the base layer. It is an object of the present invention for the laminated carton to have the inner surface of the outer layer to be bonded continuously to the outer surface layer of the base layer.
It is an object of the present invention to provide a method for a manufacturer to metalize a label or other types of freesheet or groundwood paper in a conventional manner. In accordance with the present invention, a paper is metalized and graphics are printed on the sheet. The printed sheet can then be wound in coil form and stored for subsequent application to a cellulosic substrate. Alternatively, after the metalized paper is printed, the paper can be used in an inline process, so that it is attached to a cellulosic substrate without having to be wound first.
When producing beverage carrier, the cellulosic substrate preferably consists of one or more plies of unbleached virgin Kraft pulp, while when producing a product such as cereal box, cellulosic substrate can be formed of one or more plies of recycled fibers. In a further embodiment the cellulosic substrate consists of coated unbleached Kraft board, commonly known as SUS, Solid Unbleached Sulfate, or CNK, Coated Natural Kraft.
At a carton manufacturing site, the coiled printed metalized paper is unwound and continuously applied to a surface of a moving cellulosic substrate and bonded to the substrate by an adhesive to thereby provide a laminated product.
After application of the printed metalized paper to the cellulosic substrate, the laminated product is then die cut into a plurality of sections or segments of desired shape and each section is then folded and glued to form the configuration of a box. The boxes, in flat folded shape, are shipped to the manufacturer of the product, the boxes are then opened, the product inserted and the end flaps are then glued or secured to provide the final packaged product for distribution.
In certain instances when dealing with beverage carrier, the beverage cans may be introduced into the laminated box in a refrigerated state. Subsequently, moisture may condense on the refrigerated cans, which can cause warping or disfiguration of the laminated box. To overcome this problem, a layer of water absorbent, cellulosic material, such as Kraft paper, corrugated medium, or newsprint can be applied to the inner surface of the cellulosic substrate prior to cutting and folding of the laminated sheet. The water absorbent cellulosic layer is applied to the inner surface of the substrate through use of a water resistant adhesive. The water absorbent layer can absorb any moisture which may condense on the cans within the package to prevent warping of the laminated package.
The present invention provides enhanced graphics for paperboard packaging by use of high speed printed on metalized paper, which is then bonded to a cellulosic substrate through an adhesive.